Assessment of trace metal contamination in mangrove sediments—a case study from Guadeloupe Island, Caribbean Sea

Mangroves provide essential ecosystem services, such as shoreline protection, carbon sequestration, and biodiversity conservation. However, these ecosystems face increasing threats from anthropogenic activities, particularly trace metal pollution, which tends to accumulate in sediments. While several studies have investigated trace metal contamination in tropical mangroves worldwide, data from Lesser Antilles remain limited. This study provides the first comprehensive assessment of trace metal concentrations (Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Zn) in mangrove sediments across 10 sites in Guadeloupe, covering both environmentally conserved and anthropogenically impacted environments. Results indicate overall low to moderate contamination, consistent with national reference values in conserved sites. In contrast, anthropogenically influenced sites exhibited higher contamination levels and revealed a clear gradient between site types. Localized hotspots of contamination were identified in anthropogenically impacted sites, with high concentrations of Cu, Zn, and As. Notably, Hg and Cd were quantified at very low levels and only at one site. Multivariate analyses further highlighted distinct site groupings and suggested both natural and anthropogenic sources of contamination. These findings provide new insights into the spatial distribution of trace metals in tropical insular mangroves, underscore the influence of human activities on these vulnerable ecosystems, and support future environmental monitoring and risk assessment efforts.